Sub Hunters Take a Dive Pt 2

Continuing our study this week of the demise of anti-submarine warfare in Western navies, today we examine closely the threat, and problems faced by the modern sub hunter.

Columbian DIY Subs

Cocaine smuggling semi-submersible

Within the tropical swampland of Columbia’s Pacific Coast, a naval patrol comes across a strange craft mostly prepared for launching in a make-shift shipyard. Cocaine smugglers have been constructing primitive semi-submersibles for the transport of their illegal cargo to the American market. It was a good thing the Columbian Navy discovered the vessel before it was put to sea, for once launched these home-made boats with their diesel engines can be very difficult to track even with sophisticated surveillance gear and aircraft.

“Once the semi-subs are out at sea it’s 98% impossible to detect them,” says Major Raúl Donado of Colombia’s marines.

This illustration might give a sense of the still ominous threat posed by submarines in all parts of the world. If an off-the-shelf, primitive craft constructed by smugglers, which doesn’t completely submerge is the cause of so much frustration to naval officials, imagine the use of more capable boats constructed by naval powers in a future war at sea. Such craft need not be the modern and ultra fast nuclear subs which many consider modern day capital ships themselves, but advanced diesel boats much improved from their World War 2 era predecessors.

Building a Better Shipkiller

Modern conventional subs owe their lineage to the German Type XXI U-boats built late in the war. Such craft were built in answer to the huge Allied anti-submarine armadas which by 1943 had basically driven Hitler’s submarine from the Atlantic, hence their name the “Elecktroboote”. Primarily they were built to be faster, quieter, and stay submerged longer than ever before, as Wikipedia describes here:

The key improvement in the Type XXI was greatly increased battery capacity, roughly three times that of the Type VIIC. This gave these boats enormous underwater range, and dramatically reduced the time spent near the surface. They could travel submerged at about five knots (9 km/h) for two or three days before recharging the batteries, which took less than five hours using the snorkel. The Type XXI was also much quieter than the VIIC, making it more difficult to detect when submerged.

Type XXI-the ancestor of the modern submarine

Following the war, the victorious powers all seized versions of these advanced and unique craft for their own experiments. Out of this, the US Navy devised the GUPPY program which stood for “Greater Underwater Propulsion Power Program”. Decks were made smooth with the main gun removed, snorkels were added to allow it to remain submerged while recharging the batteries. Most dramatically, the battery power was greatly increased allowing the old war-built boats to approach underwater speeds of nearly 20knots, and more for new-built vessels like USS Albacore (AGSS-569) which surpassed thirty knots in trials.

Let’s pause for a moment to take in the new picture we have just revealed. The tiny, slow, noisy submarines which spent so much time attacking on the surface during both World Wars, while still managing to become the most successful sinker of naval and merchant vessels in all history, suddenly got better. In two world wars Germany alone sank a combined total of 27.4 million gross tons of shipping (see here and here), managing to bring Britain to the brink of surrender twice, and forcing the entire industrialized world to come together in order to defeat these primitive boats. Now with some superficial alterations and more power, the scourge of the ocean could perform its mission better, and faster, being harder to detect, not even counting the enhanced capability of nuclear power!

Best Case Scenario

For the sake of argument, to those still not convinced of the threat, let us give a best case scenario and discount all the imporvements mentioned such as snorkels, smooth decks, increased power, and new Air Independent Propulsion allowing subs to sail underwater for weeks without surfacing. Just providing the most favorable image of future antisubmarine operations, let us say that the only advantage the conventional sub has is because of its ability to dive it is a little more stealthy than a surface warship. According to these figures which we posted earlier, every weapon currently carried by submarines outmatches it’s contemporary on the surface ship:

Remember also that submarines, just by diving, are impervious to anti-ship cruise missiles which has forced surface navies to vast expenditure to counter, with expensive anti-missile systems like PAAMS and Aegis. The submarines just dives. Also, there is no anti-submarine version of the cruise missile.

With the Columbian smuggler sub, we get a glimpse of non-state rogue groups now having the ability to construct primitive yet effective undersea craft which often defy the best efforts of surface ships to catch it. It doesn’t need a stretch of the imagination to see rogue terrorists groups such as Al Qaeda or Hezbollah seizing ahold this idea to use against better equipped industrialized navies such as those deployed by the West, for smuggling but also as suicide craft. In fact, such a scenario become reality recently with the Sri Lankan Army actually discovering such craft (photos here) under construction by the recently defeated terrorist group the LTTE Tamil Tigers. The Sri Lankan Sunday Times provides the details:

The largest underwater craft discovered by troops was about 35 feet in length and fitted with armour plates while the other three appeared to have been in the process of being built.
A senior Sri Lanka Navy officer told The Sunday Times that these submarines were in the experimental stage with no evidence of them being used by the LTTE for any operations. He said that if the submarines were fully developed the LTTE would have used them against the Sri Lanka Navy…A few years ago Thai authorities discovered a specially made semi-submersible submarine which was used by LTTE operatives to smuggle arms and ammunition. The submarine which was discovered in a coastal village located south of Thailand is said to be able to carry 10 tons of equipment.

Like this:

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I think one scary scenario is if the smugglers could ever figure out how to “rig” an unmanned torpedoe device that has cargo space and just launch it before ever reaching the shore to a particular grid…not that I’m giving anyone any ideas here.

I’m pretty sure the Falklands War lasted longer than a month once the RN “arrived” in theater … right? Sure, the SSNs would arrive *faster* … but how much faster?

the moment you have to come above the layer, you have come above the saftey barrier, you are at risk and you loose your advantage of submarines.

Explain that to the crew of the Chinese SSK that surfaced in the middle of a CBG recently (last couple years) that didn’t know they were there until they deliberately allowed the USN to know they were there. And that wasn’t even an SSP that can stay down for longer than a day or few.

you are at risk and you loose your advantage of submarines.

At (greater) risk … yes.
Game Over by default … not exactly.

but they loose to an SSN unless they get the jump on it

*ahem*
EVERYTHING “loses to a SUBMARINE” unless they get the jump on it. The SSN doesn’t have an exclusive monopoly on the “unless you can find me, I’ve got you dead to rights” market. Remember, SSKs and SSPs have the capability to be operationally quieter than even an SSN … making them even harder to detect (and find).

but there is another truth the RN I know has been looking at Hydrogen power instead of diesel…and SSH if you will, that will be capable of range and because of its engines being smaller and more powerful they will be able to stay under for longer; but they will still need to refuel, they will be limited by more than just the food they are able to carry.

You’re still going to need to tank oxygen (for crew and propulsion) on a hydrogen fueled boat, and the current SSP designs are already doing the oxygen side of things. The German Type 212 boats are already running on fuel cells, with hydrogen and oxygen tankage held in the space between the pressure hull and the outer light hull of the sub. Look for the return of double hulled sub design such as this to come back into vogue when building for fuel cell stacked SSH propulsion, as opposed to a hydrogen combustion (stirling cycle or otherwise). Be really nice if the tech used to store hydrogen/oxygen in submarines managed to work its way out into civilian cars (but that’s another discussion).

once they are in place, moving them costs time on station, and if you try to do it quietly will take ages; int their own area they are lethal – if you are outside that area then they are just not as big a threat.

The exact same thing can be said about SSNs. Speed is the enemy of silence, in the underwater world. Pick your poison.

As for being outside of area … if I (as a navy planner) can buy 6 SSPs for the price of 1 SSN, I feel confident in being able to cover a larger operational area with the SSPs (thus mitigating the need for them to move around quickly, somewhat) … and thereby reducing this particular “vulnerability” in the context of a national security concern for the navy as a whole.

what though you cannot argue is that any diesel sub has a disadvantage in range and length of time underneath…Oynx needed to be refuelled on its way down, and took a lot longer to arrives than the multiple SSN’s which were dispatched.

no the Falkland Islands are 8000miles from the UK, hence the tital of one of the two dissertations I did for my BA.

it is a game over advantage; I always everyone saying, Mike included, that the strength of subs is that they do not surface…the moment you have to come above the layer, you have come above the saftey barrier, you are at risk and you loose your advantage of submarines.

I am sorry about this, cause I do like SSKs they are the cheaper, cheerful system; but they loose to an SSN unless they get the jump on it; they are not that powerful the moment they have to reveal their position, as they can not hide for long enough, or get far enough away to regain their cloak of secrecy. What you say is right about submarines – but there is another truth the RN I know has been looking at Hydrogen power instead of diesel…and SSH if you will, that will be capable of range and because of its engines being smaller and more powerful they will be able to stay under for longer; but they will still need to refuel, they will be limited by more than just the food they are able to carry.

Heretic, I am sorry if you disagree they are not more pro-active mines; but that is by definition what they are; once they are in place, moving them costs time on station, and if you try to do it quietly will take ages; int their own area they are lethal – if you are outside that area then they are just not as big a threat.

You have to understand that *today* there are remarkably few global navies. As such, the nations building SSPs (primarily Sweden and Germany) don’t have responsibilities/obligations that require them to sail around the world in 80 days. Consequently, they don’t design their subs to do that … because they don’t NEED to do that.

HMS Onyx took part in the Falklands War with the Royal Navy in 1982 (look it up). She was commissioned in 1967. Last I looked, the Falkland Islands weren’t anywhere “in the neighborhood” of the British Isles off the coast of France (although I could be wrong, your mileage may vary). So your complaint that SSKs and SSPs have “short sea legs” (or however you’d like to phrase it) doesn’t hold a whole lot of water as far as I’m (and more than a few veterans of multiple navies) are concerned.

As far as thermal tracking and the like goes, I’m pretty darn sure a NUCLEAR REACTOR leaves a far larger heat trail than say… a diesel engine, or a stirling engine, or a fuel cell stack. Again, advantage non-nuclear on the thermal signature. Non-nuke boats also tend to be … smaller … than the nuclear boats, which also tends to reduce their signature (volume of water displaced by their passage, etc.).

You also seem to be under the *serious* mis-impression that an SSK/SSP is only “useful” in shallow waters, and that as soon as you get out into the big blue … somehow the SSK/SSP is a “fish out of water” or somesuch, where all their advantages “go away” because they’re not working in shallow waters anymore. This makes very little sense.

The only *meaningful* advantage that an SSN has over an SSK in open water is the ability to go down … and stay down. They submerge when leaving port, and don’t have to surface again until they return to port 3 months later at the end of their patrol. This is an *important* advantage, granted … but it is not in and of itself an automatic “Game Over” advantage … and it would be foolish to assume that an SSN will have an “easy win” every single time *just because* it’s an SSN.

Alex said “acquisition of submersible technology is only really good for smuggling”

We might have to consider the suicide role you mentioned. There seems to be quite alot of these boats around so this isn’t as far fetched as it sounds. They might also lay mines within naval traffic areas, an age old submarine mission, the nautical version of the IED.

I don’t want to overstate their capabilities, but the fact that these rogue groups are building them at all, without the need of traditional shipyards, should raise some alarm in our much smaller, mostly high tech sea forces. Here’s is a job for the corvette as the USN cutters seem to be managing them well enough.

Mike you are marrying to divergent concepts here for one scary scenario; when in fact you have one possibly scary one, and one which isn’t.

deal the isn’t 1st;
the Columbia/Al Queda aquisition of submersible technology is only really good for smuggling; those weapons which you talked about require advanced targeting and launching to be used, so if they are going to attack something with these submersibles..it probably will be a suicide mission with a bomb loaded aboard. This face makes it not so scary, as that means a fairly noisy semi-submersible will have to go straight for the nearest target; as its coming straight towards them I should hope the ships look outs will at least spot them, if not the senors and the surface ship which is faster will be able to out manouver them, and probably sink by gunfire.

whilst the ability to smuggle weapons is scary, you can do that already with a motorboat, or even easier with forged documents…both of which methods are a lot cheaper and simpler than a submersible.

now for the slightly scary scenario:
AIP and nation state built craft are usually by definition more sophisticated, we have on your blog discussed the counters to these weapons many times – it is the combined approach that wins; we also know these boats weakness…their range, even with the advances you describe they are still little more than pro-active mines. I would point out that many surveliance satelites now have thirmal and ocean penetrating radar as part of their systems…these can and are used to spot subs well before forces enter that area. Now I know mike this is not ideal, but these SSKs are best in shallow confined waters…exactly the ones that the satelites are best at spotting them in, so are aircraft. When we are dealling with open waters, then it is more difficult to spot them, but it is also more difficult for them to spot you…remember the ocean is a very very very large haystack, and convoys and CBGs are very very small needles when compared. So mike things are not so bleak as you seem to fear; afterall whatever range it is at the moment any sub starts a high speed transit to its firing position modern sonar will at least pick up its presence and give you a warning, if not point out exactly where it is.

Having read this I believed it was really informative. I appreciate you spending some time and effort to put this short article together. I once again find myself spending a significant amount of time both reading and leaving comments. But so what, it was still worthwhile!